JP3864684B2

JP3864684B2 - Joining method

Info

Publication number: JP3864684B2
Application number: JP2000266932A
Authority: JP
Inventors: 久司堀; 慎也牧田
Original assignee: Nippon Light Metal Co Ltd
Current assignee: Nippon Light Metal Co Ltd
Priority date: 2000-09-04
Filing date: 2000-09-04
Publication date: 2007-01-10
Anticipated expiration: 2020-09-04
Also published as: JP2002079383A

Description

【０００１】
【発明の属する技術分野】
本発明は、互いに融点が異なる２つの金属部材を重ね合わせた状態で摩擦攪拌接合する接合方法に関する。尚、本明細書において、アルミニウムにはアルミニウム合金も含まれている。
【０００２】
【従来の技術】
融点が異なる２つの金属部材、例えばアルミニウム部材と銅部材との接合において、ＴＩＧやＭＩＧ溶接などによる直接溶融法を用いると、接合部に金属間化合物を生成し易い。これを避けるため、上記接合には、摩擦圧接、爆発圧接、あるいはロウ付けなどの方法が用いられている。
しかし、アルミニウム部材と銅部材との接合に摩擦圧接を用いた場合、被接合部材の断面形状が、棒材や管材などに限定されてしまう。また、爆発圧接を用いた場合にも、被接合部材の断面形状が制限されると共に、コスト高になる。更に、ロウ付けを用いた場合、接合部における品質の安定性を欠くと共に、高温に加熱された場合に得られた接合製品が変形し易くなる、という問題があった。
【０００３】
以上の問題を解決して、互いに融点が異なるアルミニウム部材とその他の金属部材とを接合するため、摩擦攪拌接合を用いることが提案されている。例えば、アルミニウム部材と異種金属部材とを重ね合わせた接合部に、高速回転するプローブを接触させその摩擦熱により軟化させて摩擦攪拌接合する際、上記両部材のうち強度の高い部材側からプローブを接触させる接合方法が提案されている（特開平１０−１３７９５２号公報参照）。しかし、この接合方法では、プローブの重合部付近への挿入が困難であると共に、係るプローブを含む接合ツールの寿命も短くなるため、工程管理が煩雑で且つコスト高になるという問題があった。
【０００４】
また、図６（Ａ）に示すように、アルミニウム部材３１と銅部材３２とを重ね合わせた重合部３３付近に、接合ツール３４の回転する円柱形の回転子３６における底面３７の中心から垂下するプローブ３８を挿入し、両部材３１，３２を摩擦熱により軟化して攪拌することにより接合するに際し、上記プローブ３８を軟質のアルミニウム部材３１側から挿入する、という接合方法も提案されている（特開平１０−３２８８５５号公報参照）。この接合方法によれば、軟質のアルミニウム部材３１の可塑化が容易なため、プローブ３８の挿入も容易となり、両部材３１，３２の金属同士の攪拌もスムーズに行えるため、重合部３３付近に欠陥が発生せず接合強度が向上する、という利点を有する。
【０００５】
しかしながら、プローブ３８を含む接合ツール３４や接合条件の選定如何によっては、接合部に欠陥を生じることがある。即ち、図６（Ａ）に示すように、上記部材３１，３２への入熱は、これらとプローブ３８および底面（ショルダ）３７との摩擦に起因するが、その多くは上記底面３７との摩擦による。このため、重合部３３付近における入熱量は、底面３７寄りで多くなり、プローブ３８の先端側で少なくなる。このため、軟質のアルミニウム部材３１側からプローブ３８を挿入した場合、プローブ３８の先端付近に位置する硬質の銅部材３２への入熱量が少なくなる。この結果、図６（Ｂ）に示すように、銅部材３２中において銅材料の流動不足が生じるため、接合部Ｗにおけるプローブ３８の先端付近の位置に内部欠陥（空洞）Ｋ１を生じる、という問題がある。
一方、プローブ３８および回転子３６の回転数を上げて、プローブ３８の先端寄りの位置における入熱量を増やそうとすると、アルミニウム部材３１側への入熱量が一層増加し且つアルミニウム部材３１の流動抵抗が著しく低下する。この結果、図６（Ｃ）に示すように、前記底面３７の付近からアルミニウム部材３１の一部が外部に漏れ出すことにより表面欠陥Ｋ２を生じる、という問題がある。
【０００６】
【発明が解決すべき課題】
本発明は、以上に説明した従来の技術における問題点を解決し、融点が互いに異なる金属部材同士を摩擦攪拌接合するに際し、内部や表面付近に欠陥のない健全な接合部を確実に得られる接合方法を提供する、ことを課題とする。
【０００７】
【課題を解決するための手段】
本発明は、上記の課題を解決するため、接合ツールにおけるプローブ先端寄りの付近における入熱量を増やすこと等に着想して成されたものである。
即ち、本発明の接合方法は、融点が互いに異なる一対の金属部材を重ね合わせる工程と、上記一対の金属部材のうち、低融点側の金属部材の表面付近に円柱形の本体とその底面に突設したプローブとを有する接合ツールを配置し、且つ高融点側の金属部材における上記接合ツールと対向する裏面付近に裏当材を配置する工程と、上記接合ツールを回転させつつ上記一対の金属部材の重合部付近に進入させ且つ係る重合部の長手方向に沿って移動させることにより、上記一対の金属部材をその重合部に沿って摩擦攪拌接合する工程と、を含み、上記裏当材は、高融点側の金属部材よりも低い熱伝導率のもので、且つ加熱手段を有するものである、ことを特徴とする。
【０００８】
これによれば、接合ツールにおける本体よりも細径のプローブ先端付近のみに接触する高融点側の金属部材における摩擦熱が裏面側へ逃げる事態を阻止し、高融点側の金属部材の流動・攪拌部分における温度低下を抑制できる。このため、係る高融点側の金属部材における流動不足が解消される。しかも、プローブの先端付近と摩擦して発熱する高融点側の金属部材における摩擦熱が、当該金属部材の裏面側から放出される事態を防止でき、高融点側の金属部材における温度低下を抑制できる。更に、上記放熱を防ぐと共に裏面側から積極的に加熱することで、高融点側の金属部材の重合部付近における温度降下を防止することができる。
従って、低・高融点の２つの金属部材における重合部付近において、両部材の金属が互いに塑性流動しつつ攪拌されるため、内部欠陥および表面欠陥のない健全な接合部を形成する摩擦攪拌接合を行うことができる。
【０００９】
尚、前記摩擦攪拌接合は、固相状態で２つの金属部材を軟化させて接合する方法であり、接合部には金属間化合物を生成せず、且つ接合部の付近に熱的影響部も生じない。そこで、上記のように、２つの金属部材を低融点側および高融点側としたのは、それぞれの融点に応じて軟化点（軟化温度域）も同様な関係になることに着眼したためである。それ故、低融点側と高融点側とは、同じ加熱温度における軟質側と硬質側、低強度側と高強度側、または高硬度側と低硬度側と表現することも可能である。
また、前記接合ツールには、上記２つの金属部材よりも更に高融点で且つ硬質の金属または合金から成形されたものが用いられる。
更に、前記裏当材には、高融点側の金属部材よりも熱伝導率が低い素材からなり、且つ耐熱性を有するセラミックや金属材が用いられる。例えば、セラミック材のような耐熱性で且つ低熱伝導材が用いられ、加熱手段には、例えばヒータ線などが用いられる。
【００１０】
【発明の実施の形態】
以下において、本発明の実施に好適な形態や実施例を図面などと共に説明する。
図１は、本発明の前提となる参考形態の接合方法に関する。
図１（Ａ），（ａ）に示すように、アルミニウム合金材（低融点側の金属部材）１と無酸素銅（高融点側の金属部材）２とを重ね合わせ且つ拘束して、重合部４を形成する。アルミニウム合金材１の表面付近には、例えば高速度鋼からなる円柱形の本体１１とその底面１１ａの中心部から同軸心で突設されたプローブ１２とを含む接合ツール１０が配置される。
【００１１】
図１（ａ）に示すように、接合ツール１０の本体１１とプローブ１２の軸心は、アルミニウム合金材１の表面に対する垂線よりも約５°傾けた姿勢で配置される。係る接合ツール１０は、５００〜１５０００ｒｐｍの回転数で回転され、且つその軸心に沿って１〜３０ｋＮの押し込み力を加えられつつ上記重合部４に向けて挿入されると共に、図１（ａ）で右側に５０ｍｍ〜２メートル／分の移動速度で送られる。
図１（Ａ），（ａ）に示すように、無酸素銅２における接合ツール１０と対向する裏面付近には、断面矩形の裏当材６が重合部４に沿って配置される。この裏当材６は、無酸素銅２よりも熱伝導率が低い鋼材またはセラミックからなる。
【００１２】
図１（Ｂ），（ｂ）に示すように、回転する接合ツール１０をアルミニウム合金材１側から挿入し、そのプローブ１２を重合部４を通過させて無酸素銅２中に進入させると共に、図１（ｂ）中の直線の矢印で示すように、重合部４に沿って右方向に移動させる。この間に、アルミニウム合金材１は、接合ツール１０における本体１１の底面１１ａとプローブ１２の基端部付近とに接触し摩擦発熱して塑性・流動化する。また、無酸素銅２は、接合ツール１０のプローブ１２の先端部付近と接触して摩擦発熱して塑性・流動化する。
【００１３】
そして、アルミニウム合金材１と無酸素銅２は、互いに攪拌されると共に、接合ツール１０が離れるに従って両金属が混合状態で固化した接合部Ｗが形成される。この際、裏当材６は、無酸素銅２において発生した熱がその裏面側から放熱される事態を防ぐため、接合ツール１０のプローブ１２の先端部付近における無酸素銅２の温度降下を抑制する。この結果、重合部４付近におけるアルミニウム合金材１と無酸素銅２との発熱量の差が小さくなり、無酸素銅２の流動不足が解消されるため、内部欠陥（空洞）のない健全な接合部Ｗを得ることができる。
従って、接合ツール１０の移動に伴って、重合部４に沿った健全な接合部Ｗが形成され、アルミニウム合金材１と無酸素銅２とを強固に重ね合わせて接合した各種の接合製品（例えば、トランス端子用の導電性接合体）を得ることができる。
【００１４】
図２は、本発明の接合方法に関し、図２（Ａ），（ａ）に示すように、アルミニウム合金材（低融点側の金属部材）１と無酸素銅（高融点側の金属部材）２とを重ね合わせ且つ拘束して、重合部４を形成する。アルミニウム合金材１の表面付近には、前記同様の素材からなり且つ前記同様の本体１１およびプローブ１２を含む接合ツール１０が前記同様に傾斜して配置される。
図２（Ａ），（ａ）に示すように、無酸素銅２における接合ツール１０と対向する裏面付近には、断面矩形の裏当材８が重合部４に沿って配置される。この裏当材８も、無酸素銅２よりも熱伝導率が低い鋼材またはセラミックからなり、その内部には複数のヒータ線（加熱手段）９が内臓されている。
図２（Ｂ），（ｂ）に示すように、予めヒータ線９に通電して裏当材８を加熱した状態で、回転する接合ツール１０をアルミニウム合金材１側から挿入し、そのプローブ１２の先端寄りを重合部４を通過させて無酸素銅２に進入させると共に、図２（ｂ）中の直線の矢印で示すように、重合部４に沿って右側に移動させる。
【００１５】
以上の間に、アルミニウム合金材１は、接合ツール１０における本体１１の底面１１ａとプローブ１２の基端部とに接触して摩擦発熱して塑性・流動化すると共に、無酸素銅２も、接合ツール１０のプローブ１２の先端付近と接触して摩擦発熱して塑性・流動化する。その結果、アルミニウム合金材１と無酸素銅２は、互いに攪拌され、接合ツール１０が離れるに従って両金属材料が混合状態で固化した接合部Ｗが形成される。この際、裏当材８は、無酸素銅２における摩擦熱が裏面側から放熱される事態を防ぐと共に、内臓した各ヒータ線９により無酸素銅２を更に加熱する。このため、接合ツール１０のプローブ１２の先端部付近における無酸素銅２の温度降下を一層確実に抑制する。
この結果、無酸素銅２の流動不足が解消されるので、内部欠陥（空洞）のない健全な接合部Ｗを得ることができる。従って、接合ツール１０の移動に伴って重合部４に沿って健全な接合部Ｗが形成され、アルミニウム合金部材１と無酸素銅２とを強固に重ね合わせて接合した接合製品を得ることができる。
【００１６】
【実施例】
ここで、前記接合方法の具他的な実施例を比較例と共に説明する。
ＪＩＳ：Ａ６０６３からなり長さ２００ｍｍ×幅１００ｍｍ×厚さ５ｍｍのアルミニウム合金材１と同じサイズの無酸素銅２とを５組用意した。また、高速度鋼から成形され、直径２０ｍｍの本体１１と、直径９ｍｍで長さ６ｍｍのプローブ１２とを含む接合ツール１０を用意した。
図２（Ａ），（ａ）に示したように、各組のアルミニウム合金材１と無酸素銅２とを重ね合わせて、重合部４を各組別に形成し、各組の無酸素銅２の裏面側に同じ無酸素銅からなり、長さ２００ｍｍ×幅１００ｍｍ×厚さ１０ｍｍの共通のサイズを有する裏当材８を各組別に配置した。各組の裏当材８には、同じ配線のヒータ線９が内臓されている。そして、ヒータ線９に通電し、裏当材８の表面温度が１００℃、２００℃、４００℃、５００℃に個別に加熱された組をそれぞれ実施例１〜４とし、ヒータ線９に通電しなかった組を比較例とした。
【００１７】
各例のアルミニウム合金材１の表面側から、前記図２（Ｂ），（ｂ）に示したように、移動方向と反対側に５°傾けた接合ツール１０を、回転数７００ｒｐｍ、押し込み圧力１２．５ｋＮ、移動速度２００ｍｍ／分の同じ条件で挿入し、重合部４に沿って移動させた。各例において、無酸素銅２における接合時の発熱温度を熱電対により測定すると共に、得られた各例の接合部Ｗを切断し、露出した断面を目視により観察して欠陥の有無を調べた。それらの結果を表１に示した。
【００１８】
【表１】

【００１９】
表１の結果によれば、実施例１〜４では、裏当材８の温度にほぼ比例して無酸素銅２の温度も高くなり、且つ無酸素銅２の温度が４２０℃の実施例２と４７０℃の実施例３では、接合部Ｗに内部欠陥を生じていなかった。また、無酸素銅２の温度が３５０℃とやや低い実施例１は、微細な内部欠陥に留まり、無酸素銅２の温度が５２０℃とやや高い実施例４では、接合部Ｗの表面に微細に凹んだ表面欠陥が観察された。これらから、実施例１は加熱不足により、プローブ１２先端付近における無酸素銅２の温度低下を十分に防げず流動不足を僅かに生じ、逆に実施例４では、過加熱により、内部欠陥は阻止できたが、接合部Ｗの表面における流動抵抗がやや低下しため、微細な表面欠陥を招いたものと推定される。
一方、裏当材８を加熱しなかった比較例では、約０．２ｍｍの粗大な内部欠陥（空洞）が発見された。即ち、比較例は、無酸素銅２中において流動不足が生じたため、粗大な内部欠陥が生じたものと推定される。
以上の実施例１〜４によって、本発明の接合方法の優位性が理解されよう。
【００２０】
図３は、参考形態の接合方法に関し、図３（Ａ），（Ｂ）に示すように、この方法に用いる接合ツール１０は、高速度鋼からなる円筒形の本体１１とその底面１１ａの中心部から突出するプローブ１２を含み、該プローブ１２の先端面（先端部）１２ａに、径方向に沿った一対の十字形を呈する凸条（凹凸部）１４を突設している。
前記図１（Ａ），（ａ）のように、アルミニウム合金材（低融点側の金属部材）１と無酸素銅（高融点側の金属部材）２とを重ね合わせて拘束し、重合部４を形成する。また、アルミニウム合金材１の表面付近には、本体１１およびプローブ１２を含み且つ上記一対の凸条１４，１４を有する上記接合ツール１０を、前記同様に傾斜して配置する。但し、前記裏当材６は使用しない。
次いで、前記図１（Ｂ），（ｂ）に示したように、回転する接合ツール１０をアルミニウム合金材１側から挿入し、そのプローブ１２の先端面１２ａを重合部４を通過させて無酸素銅２中に進入させると共に、図１（ｂ）中の直線の矢印で示したように、重合部４に沿って右方向に移動させる。
【００２１】
以上の間に、アルミニウム合金材１は、接合ツール１０における本体１１の底面１１ａとプローブ１２の基端部付近とに接触して摩擦発熱して塑性・流動化すると共に、無酸素銅２も、接合ツール１０のプローブ１２の先端部および一対の凸条１４，１４に接触して摩擦発熱することにより、塑性・流動化する。
その結果、アルミニウム合金材１と無酸素銅２は、互いに攪拌され、接合ツール１０が離れるに従って両金属が混合状態で固化した接合部Ｗが形成される。この際、無酸素銅２は、プローブ１２の凸条１４にも摩擦接触し、その接触面積の増加分に応じて発熱量が増加するため、流動不足を解消することができる。この結果、内部欠陥（空洞）のない健全な接合部Ｗを重合部４に沿って形成できる。
【００２２】
また、図３（Ｃ），（ｃ）に示すように、プローブ１２の先端面１２ａに細かな立方体の突起（凹凸部）１６を格子状に多数突設した形態や、図３（Ｄ），（ｄ）に示すように、プローブ１２の先端面１２ａにリング凸条（凹凸部）１７，１８，１９を同心円状に突設した形態よっても、上記十字形で一対の凸条１４と同様の作用・効果を得ることができる。
更に、図３（Ｅ），（ｅ），（Ｆ）に示すように、接合ツール１０のプローブ１２における先端面１２ａ寄りの周面（先端部）にその軸方向に沿った凹溝（凹凸部）１３を複数形成した形態でも、上記凸条１４と同様の作用・効果を得ることができる。尚、上記凹溝１３に替えて多数の凹みを散点状に形成したり、あるいは、プローブ１２周面の凹溝１３や凹みと共に、その先端面１２ａに凸条１４、突起１６、またはリング凸条１７，１８，１９などを併設することも可能である。
【００２３】
図４は、異なる参考形態の接合方法とこれに用いる接合ツール２０に関する。
前記請求項７に相当する接合ツール２０は、図４（Ａ），（Ｂ）に示すように、例えば高速度鋼からなり、円柱形の本体２１とその底面２１ａの中心部に突設したプローブ基端部２２とを含む第１部分２０ａと、この基端部２２と同軸心のプローブ先端部２４と上記本体２１およびプローブ基端部２２の軸心孔２３を貫通する回転軸２６とを含む第２部分２０ｂと、係る第１部分２０ａと第２部分２０ｂとの間に配置した複数の軸受２８と、を含む。第１部分２０ａと第２部分２０ｂとは、モータなどの専用の駆動源に対し個別に接続されている。尚、第１・第２部分２０ａ，２０ｂ間の外端部寄りには、耐熱性のシール材２９が配置される。
【００２４】
図４（Ｃ），（Ｄ）に示すように、アルミニウム合金材（低融点側の金属部材）１と無酸素銅（高融点側の金属部材）２とを重ね合わせて拘束し、重合部４を形成する。また、アルミニウム合金材１の表面付近には、上記接合ツール２０を前記同様に傾斜して配置する。この際、第２部分２０ｂを第１部分２０ａよりも大きな回転数によって回転しつつ、接合ツール２０に１〜３０ｋＮの押し込み力を加え且つ上記重合部４付近に向けて挿入すると共に、係る接合ツール２０を図４(Ｄ)で右方向に５０ｍｍ〜２メートル／分の移動速度で移動させる。
【００２５】
以上の間に、アルミニウム合金材１は、第１部分２０ａにおける本体２１の底面２１ａとプローブ基端部２２とに接触して摩擦発熱して塑性・流動化すると共に、無酸素銅２も、第２部分２０ｂのプローブ先端部２４と接触して摩擦発熱して塑性・流動化する。その結果、アルミニウム合金材１と無酸素銅２とは、互いに攪拌され、接合ツール２０が離れるに従って両金属が混合状態で固化した接合部Ｗが形成される。一方、無酸素銅２は、第２部分２０ｂのプローブ先端部２４に摩擦接触し、その回転数の増加分に応じて発熱量が増加するため、流動不足を解消することができる。これにより、内部欠陥(空洞)のない健全な接合部Ｗを重合部４に沿って形成可能となる。
【００２６】
図５（Ａ），（Ｂ）は、異なる参考形態の接合ツール２０′を示す。
図示のように、接合ツール２０′は、円柱形の本体２１を含む第１部分２０ａと、この本体２１の軸心孔２３を貫通する回転軸２６およびその先端に位置するプローブ２５とを含む第２部分２０ｂと、係る第１部分２０ａと第２部分２０ｂとの間に配置した複数の軸受２８と、を含む。第１・第２部分２０ａ，２０ｂは、モータなどの専用の駆動源に対し個別に接続され、且つ第１・第２部分２０ａ，２０ｂ間の外端部寄りには、耐熱性のシール材２９が配置されている。
以上のような接合ツール２０′を用いても、プローブ２５を含む第２部分２０ｂの回転数を本体２１の第１部分２０ａよりも大きくすることにより、前記図４（Ｃ），（Ｄ）に示したように、摩擦による入熱量が増加して、高融点側の銅部材２において塑性・流動化が確実に行われる。一方、第１部分２０ａの回転数を小さくするので、その本体２１の底面２１ａに接触する低融点側のアルミニウム合金材１は、過度の摩擦発熱による溶融化を防ぐことができる。従って、接合ツール２０′によっても健全な接合部Ｗを形成することが可能である。
【００２７】
また、図５（Ｃ）は、更に異なる参考形態の接合ツール２０″の断面を示す。接合ツール２０″は、図５（Ｃ）に示すように、円柱形の本体２１の外周部を含む第１部分２０ａと、本体２１の軸心孔２３を貫通する太径の回転軸２６およびその底面２７の中心部から同軸心に突出するプローブ２５を含む第２部分２０ｂと、係る第１部分２０ａと第２部分２０ｂとの間に配置した複数の軸受２８と、を含む。これら第１・第２部分２０ａ，２０ｂも、モータなどの専用の駆動源に対し個別に接続され、且つ第１・第２部分２０ａ，２０ｂ間の外端部寄りには、耐熱性のシール材２９が配置される。
以上のような接合ツール２０″を用いても、接合ツール２０′と同じく前記接合ツール２０における作用・効果を同様に得ることが可能である。
【００２８】
本発明は、以上において説明した形態および実施例に限定されない。
例えば、本発明における低融点側と高融点側の金属部材は、両者の間における融点または軟化点の差が１００℃以上であるか、または、同じ加熱温度における引張強さなどの強度の差が１００Ｎ以上であるか、あるいは硬度の差が３０Ｈｖ以上であれば、異種金属やそれらの合金間の組合せは基より、同種金属の合金系同士でも適用可能である。
また、低融点側と高融点側の一対の金属部材における重ね合わせ部には、両部材の段部同士の間または雄・雌嵌合部も含まれ、且つ平面視で直線形に限らず、中間で屈曲する重合部やカーブする重合部も含まれる。
更に、前記裏当材８に設ける加熱手段は、前記ヒータ線９に限らず、放熱パイプやヒートパイプ、あるいはバーナーを内臓したラジアントチューブなども適用可能である。
また、前記接合ツール１０のプローブ１２の先端部に設ける凹凸部には、周面に刻設したネジ山や、先端面１２ａに突設する渦巻き形の凸条も含まれる。
【００２９】
【発明の効果】
以上にて説明した本発明の接合方法によれば、接合ツールにおけるプローブ先端付近のみに接触する高融点側の金属部材における摩擦熱が裏面側へ逃げる事態を阻止し、高融点側の金属部材の流動・攪拌部における温度低下を抑制できる。このため、高融点側の金属部材における流動不足が解消されるので、低・高融点の２つの金属部材における重合部付近において、両者の金属が互いに塑性・流動しつつ攪拌される。しかも、プローブの先端付近と摩擦して発熱する高融点側の金属部材における摩擦熱が、当該金属部材の裏面側から放出される事態を防止でき、高融点側の金属部材における温度低下を抑制できる。更に、上記放熱を防ぐと共に裏面側から積極的に加熱することで、高融点側の金属部材の重合部付近における温度降下を防止できる。従って、内部欠陥および表面欠陥のない健全な接合部を形成する摩擦攪拌接合を行うことができる。
【図面の簡単な説明】
【図１】（Ａ），（Ｂ）は本発明の前提となる参考形態の接合方法の概略を示す正面図、（ａ），（ｂ）はこれらの側面図。
【図２】（Ａ），（Ｂ）は本発明の接合方法の応用形態の概略を示す正面図、（ａ），（ｂ）はこれらの側面図。
【図３】（Ａ），（Ｂ）は参考形態の接合方法に用いる接合ツールの側面図または斜視図、（Ｃ），（Ｄ）は異なる参考形態の凹凸部を示す底面図、（ｃ）は（Ｃ）の参考形態の側面図、（ｄ）は（Ｄ）中のｄ−ｄ線に沿った視角における断面図、（Ｅ），（Ｆ）は更に異なる参考形態の接合ツールを示す側面図または斜視図、（ｅ）は（Ｅ）中のｅ−ｅ線に沿った視角における断面図。
【図４】（Ａ），（Ｂ）は異なる参考形態の接合方法に用いる接合ツールの側面図または断面図、（Ｃ），（Ｄ）は異なる参考形態の接合方法を示す概略図。
【図５】（Ａ），（Ｂ）は更に異なる参考形態の接合方法に用いる異なる形態の接合ツールの側面図または断面図、（Ｃ）は更に異なる形態の接合ツールの断面図。
【図６】（Ａ）は従来の摩擦攪拌接合を示す概略図、（Ｂ），（Ｃ）はこれにより得られた接合部付近を示す断面図。
【符号の説明】
１………………アルミニウム合金材（低融点側の金属部材）
２………………無酸素銅（高融点側の金属部材）
４………………重合部
８………………裏当材
９………………ヒータ線（加熱手段）
１０……………接合ツール
１１……………本体
１１……………底面
１２……………プローブ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bonding how to friction stir welding in a state of superposition of two metal members having a melting point different from each other. In the present specification, aluminum includes an aluminum alloy.
[0002]
[Prior art]
When a direct melting method such as TIG or MIG welding is used in joining two metal members having different melting points, for example, an aluminum member and a copper member, an intermetallic compound is likely to be generated at the joint. In order to avoid this, a method such as friction welding, explosion welding or brazing is used for the joining.
However, when friction welding is used for joining the aluminum member and the copper member, the cross-sectional shape of the member to be joined is limited to a bar or a pipe. In addition, when explosion welding is used, the cross-sectional shape of the member to be joined is limited and the cost is increased. Furthermore, when brazing is used, there is a problem in that the quality of the bonded portion is not stable and the bonded product obtained when heated to a high temperature is easily deformed.
[0003]
It has been proposed to use friction stir welding in order to solve the above problems and join an aluminum member having a different melting point and another metal member. For example, when a probe that rotates at high speed is brought into contact with a joint where an aluminum member and a dissimilar metal member are overlapped, and the friction stir heat is applied and the friction stir welding is performed, the probe is inserted from the side of the member having high strength among the two members. A joining method for contacting is proposed (refer to Japanese Patent Laid-Open No. 10-137592). However, this joining method has a problem that it is difficult to insert the probe in the vicinity of the overlapping portion, and the life of the joining tool including the probe is shortened, so that the process management is complicated and expensive.
[0004]
Further, as shown in FIG. 6A, it hangs down from the center of the bottom surface 37 of the cylindrical rotor 36 where the joining tool 34 rotates, in the vicinity of the overlapping portion 33 where the aluminum member 31 and the copper member 32 are overlapped. There has also been proposed a joining method in which the probe 38 is inserted from the side of the soft aluminum member 31 when the probe 38 is inserted and the

members

31 and 32 are joined by being softened by frictional heat and stirred. (See Kaihei 10-328855). According to this joining method, since the soft aluminum member 31 can be easily plasticized, the probe 38 can be easily inserted, and the metals of the

members

31 and 32 can be smoothly agitated. Does not occur, and the bonding strength is improved.
[0005]
However, depending on the selection of the bonding tool 34 including the probe 38 and the bonding conditions, a defect may occur in the bonded portion. That is, as shown in FIG. 6 (A), heat input to the

members

31 and 32 is caused by friction between them and the probe 38 and the bottom surface (shoulder) 37, and most of the heat input is friction with the bottom surface 37. by. For this reason, the amount of heat input in the vicinity of the overlapping portion 33 increases near the bottom surface 37 and decreases on the tip side of the probe 38. For this reason, when the probe 38 is inserted from the soft aluminum member 31 side, the amount of heat input to the hard copper member 32 located near the tip of the probe 38 is reduced. As a result, as shown in FIG. 6B, the copper material 32 is insufficiently flowed in the copper member 32, so that an internal defect (cavity) K <b> 1 occurs at a position near the tip of the probe 38 in the joint W. There is.
On the other hand, if the number of rotations of the probe 38 and the rotor 36 is increased to increase the amount of heat input at a position near the tip of the probe 38, the amount of heat input to the aluminum member 31 side further increases and the flow resistance of the aluminum member 31 is reduced. It drops significantly. As a result, as shown in FIG. 6C, there is a problem in that a surface defect K2 is generated when a part of the aluminum member 31 leaks from the vicinity of the bottom surface 37 to the outside.
[0006]
[Problems to be Solved by the Invention]
The present invention solves the problems in the prior art described above, and when a metal member having different melting points is friction stir welded, it is possible to reliably obtain a sound joint with no defects inside or near the surface. to provide mETHODS, it is an object of the present invention.
[0007]
[Means for Solving the Problems]
The present invention for solving the above problems, has been made by inspired like to increase the heat input in the pulp lobe tip close vicinity of put the welding tool.
In other words, junction method of the present invention includes the steps of superimposing a different pair of metal members melting point, among the pair of metal members, the body and its bottom surface of the cylindrical near the surface of the low melting point side of the metal member A step of disposing a bonding tool having a protruding probe and disposing a backing material in the vicinity of the back surface of the metal member on the high melting point side facing the bonding tool; and the pair of metals while rotating the bonding tool by moving along the longitudinal direction overlapping portions of the overlapping portion of and is advanced to the vicinity of the member, viewed including the steps, the friction stir joining along their overlapping portions of the pair of metal members, the backing material Is characterized by having a thermal conductivity lower than that of the metal member on the high melting point side and having a heating means .
[0008]
According to this, it is possible to prevent the frictional heat in the high melting point metal member contacting only near the tip of the probe having a smaller diameter than the main body of the welding tool from escaping to the back side, and the flow and stirring of the high melting point metal member. The temperature drop in the portion can be suppressed. For this reason, the lack of flow in the metal member on the high melting point side is eliminated. In addition, it is possible to prevent the frictional heat in the high melting point metal member that generates heat by friction with the vicinity of the tip of the probe from being released from the back side of the metal member, and to suppress the temperature drop in the high melting point metal member. . Furthermore, by preventing the heat dissipation and positively heating from the back side, it is possible to prevent a temperature drop in the vicinity of the overlapping portion of the metal member on the high melting point side .
Therefore, in the vicinity of the overlapping portion of the two low and high melting point metal members, the metals of both members are agitated while plastically flowing to each other, so that friction stir welding that forms a sound joint without internal defects and surface defects is performed. It can be carried out.
[0009]
The friction stir welding is a method in which two metal members are softened and joined in a solid state, and an intermetallic compound is not formed in the joint, and a thermally affected part is also generated in the vicinity of the joint. Absent. Therefore, as described above, the reason why the two metal members are set to the low melting point side and the high melting point side is that the softening point (softening temperature range) has a similar relationship according to the melting points. Therefore, the low melting point side and the high melting point side can also be expressed as a soft side and a hard side, a low strength side and a high strength side, or a high hardness side and a low hardness side at the same heating temperature.
In addition, a tool formed from a hard metal or alloy having a melting point higher than that of the two metal members is used as the joining tool.
Furthermore, the backing material is made of a material having a lower thermal conductivity than that of the metal member on the high melting point side, and a ceramic or metal material having heat resistance is used. For example , a heat-resistant and low thermal conductive material such as a ceramic material is used, and for example, a heater wire or the like is used as the heating means.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
In the following, preferred embodiments and examples for implementing the present invention will be described with reference to the drawings.
Figure 1 relates to junction method of Reference Embodiment underlying the present invention.
As shown in FIGS. 1A and 1A, an aluminum alloy material (a metal member on the low melting point side) 1 and an oxygen-free copper (a metal member on the high melting point side) 2 are overlapped and restrained to overlap each other. 4 is formed. Near the surface of the aluminum alloy material 1, a joining tool 10 including a cylindrical main body 11 made of, for example, high-speed steel and a probe 12 protruding coaxially from the center of the bottom surface 11a is disposed.
[0011]
As shown in FIG. 1A, the axes of the main body 11 and the probe 12 of the joining tool 10 are arranged in a posture inclined about 5 ° with respect to the normal to the surface of the aluminum alloy material 1. The joining tool 10 is rotated at a rotational speed of 500 to 15000 rpm, and is inserted toward the overlapping portion 4 while being applied with a pushing force of 1 to 30 kN along its axis, and FIG. And is sent to the right side at a moving speed of 50 mm to 2 meters / minute.
As shown in FIGS. 1A and 1A, a backing material 6 having a rectangular cross section is disposed along the overlapping portion 4 in the vicinity of the back surface of the oxygen-free copper 2 facing the bonding tool 10. The backing material 6 is made of steel or ceramic having a lower thermal conductivity than the oxygen-free copper 2.
[0012]
As shown in FIGS. 1 (B) and 1 (b), a rotating joining tool 10 is inserted from the aluminum alloy material 1 side, and the probe 12 is allowed to enter the oxygen-free copper 2 through the overlapping portion 4, As indicated by the straight arrows in FIG. 1B, the rightward movement is made along the overlapping portion 4. During this time, the aluminum alloy material 1 comes into contact with the bottom surface 11a of the main body 11 and the vicinity of the proximal end portion of the probe 12 in the joining tool 10, and generates friction and generates plasticity and fluidization. Further, the oxygen-free copper 2 comes into contact with the vicinity of the tip end portion of the probe 12 of the joining tool 10 and generates heat by friction to plasticize and fluidize.
[0013]
Then, the aluminum alloy material 1 and the oxygen-free copper 2 are stirred together, and a joint W is formed in which both metals are solidified in a mixed state as the joining tool 10 is separated. At this time, the backing material 6 suppresses the temperature drop of the oxygen-free copper 2 in the vicinity of the tip of the probe 12 of the bonding tool 10 in order to prevent the heat generated in the oxygen-free copper 2 from being radiated from the back surface side. To do. As a result, the difference in calorific value between the aluminum alloy material 1 and the oxygen-free copper 2 in the vicinity of the polymerized portion 4 is reduced, and the lack of flow of the oxygen-free copper 2 is eliminated. Part W can be obtained.
Accordingly, as the bonding tool 10 moves, a sound bonded portion W is formed along the overlapping portion 4, and various bonded products (for example, the aluminum alloy material 1 and the oxygen-free copper 2 are firmly overlapped and bonded) , A conductive joint for a transformer terminal) can be obtained.
[0014]
Figure 2 relates to the bonding how the present invention, as shown in FIG. 2 (A), (a), an aluminum alloy material (low-melting side of the metal member) 1 and the oxygen-free copper (refractory side metal member And 2) are overlapped and constrained to form the overlapping portion 4. Near the surface of the aluminum alloy material 1, a joining tool 10 made of the same material as described above and including the same main body 11 and probe 12 is inclined as described above.
As shown in FIGS. 2A and 2A, a backing material 8 having a rectangular cross section is disposed along the overlapping portion 4 in the vicinity of the back surface of the oxygen-free copper 2 facing the bonding tool 10. The backing material 8 is also made of steel or ceramic having a lower thermal conductivity than the oxygen-free copper 2, and a plurality of heater wires (heating means) 9 are built therein.
As shown in FIGS. 2 (B) and 2 (b), a rotating welding tool 10 is inserted from the aluminum alloy material 1 side in a state in which the heater wire 9 is energized in advance and the backing material 8 is heated. As shown by the straight arrow in FIG. 2 (b), it is moved to the right along the overlapping portion 4 while passing through the overlapping portion 4 and entering the oxygen-free copper 2.
[0015]
During the above, the aluminum alloy material 1 is brought into contact with the bottom surface 11a of the main body 11 and the proximal end portion of the probe 12 in the joining tool 10 to generate heat and generate plasticity and fluidity. The tool 10 comes into contact with the vicinity of the tip of the probe 12 and generates heat by friction to plasticize and fluidize. As a result, the aluminum alloy material 1 and the oxygen-free copper 2 are agitated with each other, and a joining portion W is formed in which both metal materials are solidified in a mixed state as the joining tool 10 is separated. At this time, the backing material 8 prevents the frictional heat in the oxygen-free copper 2 from being radiated from the back surface side, and further heats the oxygen-free copper 2 by the built-in heater wires 9. For this reason, the temperature drop of the oxygen-free copper 2 in the vicinity of the distal end portion of the probe 12 of the joining tool 10 is more reliably suppressed.
As a result, the lack of flow of the oxygen-free copper 2 is eliminated, so that a healthy joint W having no internal defects (cavities) can be obtained. Accordingly, a sound bonded portion W is formed along the overlapping portion 4 as the bonding tool 10 moves, and a bonded product in which the aluminum alloy member 1 and the oxygen-free copper 2 are firmly overlapped and bonded can be obtained. .
[0016]
【Example】
Here it will be described together with comparative examples ingredients other examples of the bonding method.
Five sets of an oxygen-free copper 2 having the same size as the aluminum alloy material 1 made of JIS: A6063 and having a length of 200 mm × width of 100 mm × thickness of 5 mm were prepared. Moreover, the joining tool 10 which was shape | molded from the high speed steel and included the main body 11 with a diameter of 20 mm and the probe 12 with a diameter of 9 mm and a length of 6 mm was prepared.
As shown in FIGS. 2 (A) and 2 (a), each set of aluminum alloy material 1 and oxygen-free copper 2 are overlapped to form superposed portions 4 for each set, and each set of oxygen-free copper 2 A backing material 8 made of the same oxygen-free copper and having a common size of length 200 mm × width 100 mm × thickness 10 mm was arranged for each group on the back side. Each set of backing material 8 contains a heater wire 9 of the same wiring. Then, the heater wire 9 was energized, and the groups in which the surface temperature of the backing material 8 was individually heated to 100 ° C., 200 ° C., 400 ° C., and 500 ° C. were set as Examples 1 to 4 , respectively. The group that did not exist was used as a comparative example .
[0017]
As shown in FIGS. 2 (B) and 2 (b), the joining tool 10 tilted 5 ° from the surface side of the aluminum alloy material 1 of each example to the opposite side to the moving direction has a rotation speed of 700 rpm and an indentation pressure of 12 It was inserted under the same conditions of 0.5 kN and a moving speed of 200 mm / min, and moved along the overlapping portion 4. In each example, the exothermic temperature at the time of joining in the oxygen-free copper 2 was measured with a thermocouple, the joint W of each obtained example was cut, and the exposed cross section was visually observed to check for the presence of defects. . The results are shown in Table 1 .
[0018]
[Table 1]

[0019]
According to the results of Table 1, in Examples 1-4, approximately the temperature proportional to oxygen-free copper 2 also increases the temperature of the backing strip 8, and the temperature of the oxygen-free copper 2 of 420 ° C. Example 2 In Example 3 at 470 ° C., no internal defect occurred in the joint W. Further, Example 1 in which the temperature of the oxygen-free copper 2 is as low as 350 ° C. remains as a minute internal defect, and in Example 4 in which the temperature of the oxygen-free copper 2 is slightly high as 520 ° C., the surface of the joint W is fine. Recessed surface defects were observed. From these, in Example 1, due to insufficient heating, the temperature drop of the oxygen-free copper 2 near the tip of the probe 12 cannot be sufficiently prevented, resulting in slight flow shortage. In contrast, in Example 4 , internal defects are prevented by overheating. Although it was possible, the flow resistance on the surface of the joint W was slightly lowered, and it is presumed that fine surface defects were caused.
On the other hand, in the comparative example in which the backing material 8 was not heated, coarse internal defects (cavities) of about 0.2 mm were found. In other words, in the comparative example , it was estimated that coarse internal defects occurred because of insufficient flow in the oxygen-

free

copper 2.
From the above Examples 1 to 4 , the superiority of the joining method of the present invention will be understood.
[0020]
FIG. 3 relates to a joining method of a reference form . As shown in FIGS. 3 (A) and 3 (B), a joining tool 10 used in this method includes a cylindrical main body 11 made of high-speed steel and the center of its bottom face 11a. The probe 12 protrudes from the portion, and a pair of ridges (concave / convex portions) 14 having a cross shape along the radial direction project from a tip surface (tip portion) 12 a of the probe 12.
As shown in FIGS. 1A and 1A, an aluminum alloy material (a metal member on the low melting point side) 1 and an oxygen-free copper (a metal member on the high melting point side) 2 are superposed and restrained to overlap each other. Form. Further, in the vicinity of the surface of the aluminum alloy material 1, the joining tool 10 including the main body 11 and the probe 12 and having the pair of

ridges

14 and 14 is disposed in an inclined manner as described above. However, the backing material 6 is not used.
Next, as shown in FIGS. 1B and 1B, the rotating joining tool 10 is inserted from the aluminum alloy material 1 side, and the tip surface 12a of the probe 12 is passed through the overlapping portion 4 to make oxygen-free. While making it infiltrate into copper 2, as shown with the straight arrow in FIG.1 (b), it moves to the right direction along the superposition | polymerization part 4. FIG.
[0021]
During the above, the aluminum alloy material 1 is brought into contact with the bottom surface 11a of the main body 11 in the joining tool 10 and the vicinity of the proximal end portion of the probe 12 to generate heat by friction and plasticization and fluidization. When the tip of the probe 12 of the welding tool 10 and the pair of

ridges

14 and 14 come into contact with each other and generate frictional heat, plasticity and fluidization occur.
As a result, the aluminum alloy material 1 and the oxygen-free copper 2 are agitated with each other, and a joining portion W is formed in which both metals are solidified in a mixed state as the joining tool 10 is separated. At this time, the oxygen-free copper 2 also comes into frictional contact with the ridges 14 of the probe 12 and the amount of heat generation increases according to the increase in the contact area, so that the lack of flow can be solved. As a result, a healthy joint W having no internal defects (cavities) can be formed along the overlapping portion 4.
[0022]
Further, as shown in FIGS. 3C and 3C, a configuration in which a large number of fine cubic projections (uneven portions) 16 are provided in a lattice shape on the distal end surface 12a of the probe 12, or FIGS. As shown in (d), even if the ring ridges (concave / convex portions) 17, 18, and 19 are provided concentrically on the tip surface 12a of the probe 12, the cross shape is the same as that of the pair of ridges 14. Actions and effects can be obtained.
Further, as shown in FIGS. 3E, 3E, and 3F, a groove (uneven portion) along the axial direction is formed on the peripheral surface (tip portion) of the probe 12 of the welding tool 10 near the tip surface 12a. ) Even in a form in which a plurality of 13 are formed, the same action and effect as the above-mentioned ridge 14 can be obtained. It should be noted that a large number of dents are formed in the form of dots in place of the dent grooves 13, or together with the dent grooves 13 and dents on the peripheral surface of the probe 12, the ridges 14, protrusions 16 or ring protrusions on the tip surface 12a.

Articles

17, 18, 19 and the like can also be provided.
[0023]
FIG. 4 relates to a joining method of a different reference form and a joining tool 20 used therefor.
As shown in FIGS. 4A and 4B, the joining tool 20 corresponding to the seventh aspect is made of, for example, high-speed steel and protrudes from the center of the cylindrical main body 21 and its bottom surface 21a. A first portion 20 a including a base end portion 22, a probe distal end portion 24 coaxial with the base end portion 22, and a rotation shaft 26 penetrating through the main body 21 and the axial hole 23 of the probe base end portion 22 are included. It includes a second portion 20b and a plurality of bearings 28 disposed between the first portion 20a and the second portion 20b. The first portion 20a and the second portion 20b are individually connected to a dedicated drive source such as a motor. A heat-resistant sealing material 29 is disposed near the outer end between the first and

second portions

20a and 20b.
[0024]
As shown in FIGS. 4C and 4D, an aluminum alloy material (low-melting-point side metal member) 1 and oxygen-free copper (high-melting-point side metal member) 2 are overlapped and restrained to overlap each other. Form. In addition, the joining tool 20 is disposed near the surface of the aluminum alloy material 1 in the same manner as described above. At this time, while the second portion 20b is rotated at a rotational speed greater than that of the first portion 20a, a pushing force of 1 to 30 kN is applied to the joining tool 20 and inserted toward the vicinity of the overlapping portion 4, and the joining tool 20 is moved rightward in FIG. 4D at a moving speed of 50 mm to 2 meters / minute.
[0025]
As described above, the aluminum alloy material 1 is brought into contact with the bottom surface 21a of the main body 21 and the probe base end portion 22 in the first portion 20a to generate friction and generate plasticity and fluidity. The two parts 20b come into contact with the probe tip 24 to generate friction and generate plasticity and fluidity. As a result, the aluminum alloy material 1 and the oxygen-free copper 2 are agitated with each other, and a joining portion W is formed in which both metals are solidified in a mixed state as the joining tool 20 is separated. On the other hand, the oxygen-free copper 2 is in frictional contact with the probe tip 24 of the second portion 20b, and the calorific value increases in accordance with the increase in the number of rotations, so that the lack of flow can be resolved. As a result, a sound joint W having no internal defects (cavities) can be formed along the overlapping portion 4.
[0026]
FIGS. 5A and 5B show a welding tool 20 ′ having a different reference form.
As shown in the figure, the joining tool 20 ′ includes a first portion 20 a including a cylindrical main body 21, a rotating shaft 26 that penetrates the axial center hole 23 of the main body 21, and a probe 25 positioned at the tip thereof. And a plurality of bearings 28 disposed between the first portion 20a and the second portion 20b. The first and

second portions

20a and 20b are individually connected to a dedicated drive source such as a motor, and near the outer end between the first and

second portions

20a and 20b, a heat resistant sealing material 29 is provided. Is arranged.
Even when the joining tool 20 ′ as described above is used, the rotational speed of the second portion 20b including the probe 25 is made larger than that of the first portion 20a of the main body 21, so that the above-described FIGS. As shown, the amount of heat input due to friction increases, and plasticity and fluidization are reliably performed in the high melting point copper member 2. On the other hand, since the rotation speed of the first portion 20a is reduced, the low melting point side aluminum alloy material 1 in contact with the bottom surface 21a of the main body 21 can be prevented from melting due to excessive frictional heat generation. Accordingly, it is possible to form a sound joint W with the joining tool 20 '.
[0027]
Further, FIG. 5C shows a cross-section of a joining tool 20 ″ of still another reference form. The joining tool 20 ″ includes a first part including an outer peripheral portion of a cylindrical main body 21, as shown in FIG. A second portion 20b including a first portion 20a, a large-diameter rotating shaft 26 penetrating the shaft hole 23 of the main body 21, and a probe 25 projecting coaxially from the center of the bottom surface 27; and the first portion 20a A plurality of bearings 28 disposed between the second portion 20b and the second portion 20b. These first and

second portions

20a and 20b are also individually connected to a dedicated drive source such as a motor, and a heat-resistant sealing material is provided near the outer end between the first and second portions 20a and 20b. 29 is arranged.
Even when the welding tool 20 ″ as described above is used, it is possible to obtain the same operation and effect in the welding tool 20 as in the welding tool 20 ′.
[0028]
The present invention is not limited to the embodiments and examples described above.
For example, the metal member on the low melting point side and the high melting point side in the present invention has a difference in melting point or softening point between them of 100 ° C. or higher, or a difference in strength such as tensile strength at the same heating temperature. If it is 100 N or more, or if the difference in hardness is 30 Hv or more, the combination of different metals and their alloys can be applied to the same type of metal alloys as well as the base.
In addition, the overlapping portion of the pair of metal members on the low melting point side and the high melting point side includes the stepped portions of both members or a male / female fitting portion, and is not limited to a straight shape in a plan view. A polymer part that is bent in the middle and a polymer part that curves are also included.
Furthermore, the heating means provided on the backing material 8 is not limited to the heater wire 9, and a heat radiating pipe, a heat pipe, a radiant tube with a built-in burner, or the like is also applicable.
In addition, the concavo-convex portion provided at the distal end portion of the probe 12 of the joining tool 10 includes screw threads engraved on the peripheral surface and spiral ridges protruding from the distal end surface 12a.
[0029]
【The invention's effect】
According to the onset Ming joining method described in above, to prevent a situation in which the frictional heat in the refractory side of the metal member contacting only near the probe tip in the bonding tool escapes to the back side, the refractory side metal member The temperature drop in the flow / stirring section can be suppressed. For this reason, since the lack of flow in the metal member on the high melting point side is resolved, the two metals are agitated while being plastically and flowing with each other in the vicinity of the overlapping portion of the two metal members having low and high melting points. In addition, it is possible to prevent the frictional heat in the high melting point metal member that generates heat by friction with the vicinity of the tip of the probe from being released from the back side of the metal member, and to suppress the temperature drop in the high melting point metal member. . Furthermore, by preventing the heat dissipation and positively heating from the back side, it is possible to prevent a temperature drop in the vicinity of the overlapping portion of the metal member on the high melting point side . Accordingly, it is possible to perform friction stir welding that forms a sound joint without internal defects and surface defects.
[Brief description of the drawings]
FIGS. 1A and 1B are front views showing an outline of a joining method according to a reference embodiment as a premise of the present invention , and FIGS. 1A and 1B are side views thereof.
Figure 2 (A), (B) is a front view showing a schematic modified embodiment of the present onset Ming bonding method, (a), (b) these side views.
FIGS. 3A and 3B are a side view or a perspective view of a joining tool used in a joining method of a reference form, FIGS. 3C and 3D are bottom views showing uneven portions of different reference forms, and FIG. Is a side view of the reference form of (C), (d) is a cross-sectional view at a viewing angle along the line dd in (D), and (E) and (F) are side views showing a welding tool of another reference form. The figure or a perspective view, (e) is sectional drawing in the viewing angle along the ee line in (E).
FIGS. 4A and 4B are a side view or a cross-sectional view of a joining tool used in a joining method of different reference forms, and FIGS. 4C and 4D are schematic views showing a joining method of different reference forms .
FIGS. 5A and 5B are side views or cross-sectional views of different types of bonding tools used in the bonding method of different reference forms, and FIG. 5C is a cross-sectional view of still different types of bonding tools.
FIGS. 6A and 6B are schematic views showing conventional friction stir welding, and FIGS. 6B and 6C are cross-sectional views showing the vicinity of a joint obtained as a result.
[Explanation of symbols]
1 ……………… Aluminum alloy material (metal member on the low melting point side)
2 ……………… Oxygen-free copper (high melting point metal member)
4 ……………… Polymerization part 8 ……………… Backing material 9 ……………… Heater wire (heating means)
10 …………… Joining tool 11 …………… Body 11 …………… Bottom 12…… Probe

Claims

Superimposing a pair of metal members having different melting points;
Of the pair of metal members, a joining tool having a cylindrical main body and a probe projecting from the bottom surface is disposed near the surface of the metal member on the low melting point side, and the joining tool in the metal member on the high melting point side Placing a backing material near the back surface opposite to
The pair of metal members are friction stir welded along the overlapped portion by rotating the joining tool and entering the vicinity of the overlapped portion of the pair of metal members and moving along the longitudinal direction of the overlapped portion. and the process, only including,
The backing material has a thermal conductivity lower than that of the metal member on the high melting point side and has a heating means .
The joining method characterized by the above-mentioned.